High chloride, min. resistivity & corrosion

[Muddywaters]

I want to know if you have any papers on the relationship between elevated levels of chlorides (and sometimes sulfates) and reduction in resistivity. The questions are being raised with regard to the PTI manuals recommendations that chloride levels in excess of 200 ppm will mandate special treatments of the cable ends, which will increase costs.

1. Now in relatively arid environments like Arizona, chloride levels can be as high as 500-1000ppm with no ill effects. However, if these properties have lean to fat clay near surface soils and once irrigation begins, will these clay soils (which may never have been saturated) begin losing resistivity as the in-situ water content increases?


2. Do you have any technical papers on high chloride (and / or sulfates) and the resulting effects on minimum resistivity?


3. Can elevated chloride (and / or sulfates) levels cause a lowering of resistivity levels?


4. Typically, what levels of elevated chloride (and / or sulfates) have you seen that begin corrosion of steel??


5. What combinations of chloride-sulfate-resistivity numbers have you seen that are corrosive to metal??


6. Do you have any papers on in-situ moisture and its influence on resistivity?

 

[mamaPE]

Hi Muddywaters,

I've got the same questions that you have. Have you ever found any answers?

 

[Muddywaters]

Hello MamaPE.
No. I have not received answers to my questions. I have sent the questions to many people who specialize in corrosion. I will share any knowledge gained - if they reply.
MW

 

[civilperson]

The chloride levels refer to concrete, not soil.

 

[mamaPE]

"The chloride levels refer to concrete, not soil."

Actually, I'm talking about chloride levels in the soil. The post-tension institute has a requirement regarding chlorides in the soil. I'm trying to learn more about that requirement and the reasons behind it.